New telescope to unlock mysteries of the cosmos

The James Webb Space Telescope is set to launch after decades of work. Mission critical: Unravel the most enduring mysteries in space.

Is there life on other planets? How did the first stars form? What happened in the turbulent early days of the universe?

These are the tantalizing questions that the James Webb Space Telescope is meant to investigate.

After more than three decades of development, the tennis court-sized observatory is set to launch into orbit around the sun this month. It will be able to see deeper into space and in greater detail than any space or ground-based telescope to date.

The telescope’s mission is to unravel the most enduring mysteries in space, peering through more than 13 billion years of cosmic history with instruments sensitive enough to sniff out the atmospheres of exoplanets — including possibly faint biosignatures of alien life — and examine previously undetectable regions of space.

NASA is calling this an “Apollo moment” — a giant leap forward that could revolutionize our understanding of the universe and humanity’s place in it.

Some 40 million hours of work by thousands of scientists and engineers across three space agencies have gone into building the Webb telescope. And now, it is finally ready to come online.

Billed as the successor to the Hubble Space Telescope, the $10 billion Webb observatory is the largest and most powerful space telescope built to date.

At approximately 13,700 pounds, the telescope’s mass is roughly equivalent to a school bus.

Fully extended, it’s about the length of a tennis court.

The telescope’s primary mirror, which collects light from objects in the cosmos, is key to how much it can observe. The larger an observatory’s mirror, the more sensitive it is and the more detail it can pick up.

The Webb telescope’s honeycomb-shaped mirror measures about 270 square feet and is made up of 18 hexagonal segments that will unfold after launch.

Each gold-coated segment has been constructed to be perfectly aligned to focus and function as a single unit. And to do so properly, the mirror needs to be superchilled to cryogenic temperatures — cooler than minus 370 degrees Fahrenheit.

The Webb telescope’s mirror will be the largest to ever fly in space. It is nearly three times bigger than Hubble’s primary mirror, giving Webb a bigger field of view and enabling it to capture even more stunning photos than its famous predecessor.

A diamond-shaped sunshield is intended to help block heat from the sun and keep the observatory’s mirror and science instruments extremely cold.

This is essential for the telescope to pick up the faintest and most distant heat signals in the universe, without interference from the Earth or the sun.

The Webb telescope’s infrared “eyes” will be able to probe parts of space that were previously invisible to other observatories and that are beyond the visible range of the human eye.

Telescopes essentially function as time machines because it takes time for light to travel through space. The Webb observatory will be able to see farther in the universe than ever before, and therefore farther back in time. This means that astronomers will have the chance to study primitive stars and galaxies from the earliest days of the universe.

Webb’s long range

≈12.5 Present day ≈13 13.4 13.7 BIG BANG DARK AGE FIRST STARS FIRST GALAXIES MODERN UNIVERSE Hubble’s limit Webb’s limit Billions of years in the past ≈12.5 ≈13 13.4 13.7 Present day Hubble’s limit Webb’s limit Billions of years in the past MODERN UNIVERSE FIRST GALAXIES FIRST STARS DARK AGE BIG BANG

Unlike Hubble, which sees primarily visible light, the Webb telescope will gaze at infrared light, which can pierce through thick veils of cosmic gas and dust that might otherwise obscure some celestial objects from view.

NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI)

NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI)

It’s not just the instruments on board that set the Webb telescope apart. Part of what makes the mission so challenging — and potentially so rewarding — is its destination almost a million miles away from Earth.

The telescope will launch on an Ariane 5 rocket from a spaceport in Kourou, French Guiana, on Dec. 25.

It will then spend about a month journeying nearly 1 million miles to a point in space where the observatory can stay aligned with Earth as it orbits the sun.

The destination is known as the second Lagrange, or L2, point. It’s one of five positions in space where the gravitational acceleration from two large bodies — in this case, the sun and Earth — balance out, making it a gravitational sweet spot where the Webb telescope can remain in a stable orbit.

The telescope’s special orbit around the L2 point also keeps only one side of the observatory permanently facing the Earth and sun. This helps shield the telescope’s ultracold instruments from heat and light that could interfere with its observations.

The telescope’s location in space is critical for its mission, but it’s also incredibly risky. At almost a million miles away, there’s no way to fix anything that could go wrong.

And because of its size, the Webb telescope needs to be folded up for launch. Once in space, the observatory will undergo an intricate, monthlong unfurling process that NASA has nicknamed …

 “29 days on the edge.”

In the first week after launch, the sunshield’s five layers will begin to unfold.

Next, the telescope’s mirror segments will extend as it travels to its destination.

Throughout this process, the sunshield will begin cooling the observatory down. Once the telescope arrives at its L2 orbit and reaches cryogenic temperatures, the telescope’s cameras and other science instruments will begin calibrating.

Around six months after launch, the telescope will be ready to snap its first images.

Until then, nerves will be running high as NASA and its international partners face some of the highest stakes of the mission.

If it fails, there will be no way to rescue the $10 billion project. And with the Hubble Space Telescope potentially nearing the end of its long life, the loss of a next-generation observatory would be a devastating setback for space science and astronomy.

But if it’s successful, the Webb telescope will provide unparalleled views of the cosmos and could yield untold discoveries that help scientists piece together the origin and evolution of the universe.

Engineers and technicians assemble the James Webb Space Telescope, on Nov. 2, 2016 at NASA's Goddard Space Flight Center in Greenbelt, Md. (Alex Wong / Getty Images)

Engineers and technicians assemble the James Webb Space Telescope, on Nov. 2, 2016 at NASA's Goddard Space Flight Center in Greenbelt, Md. (Alex Wong / Getty Images)

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